Retrograde spread of BoNT/A effects in facial motoneurons. A , Immunoblotting showing expression of cleaved SNAP-25 in the facial nucleus 3 d after BoNT/A injection into the whisker pad. Nor, Tissue from a normal uninjected animal. One hundred micrograms of protein were loaded per lane. β-Tubulin, Internal standard. B , Confocal image of facial motoneurons (NeuN staining, green) surrounded by cleaved SNAP-25-immunopositive profiles (red). Scale bar, 20 μm.